A time-honored industrial method for producing butadiene is back in the spotlight.
Key materials for making car tires and sneaker soles could potentially be produced sustainably, following a new analysis of old catalytic processes. Butadiene, an essential component of synthetic rubber, is currently produced by the petrochemical industry from fossil resources. But it can be efficiently made in a one-step reaction from renewable ethanol and uses the latest version of a rare old catalyst.
“Butadiene is currently produced as a by-product of the petrochemical industry, which could lead to its supply shortage,” says San Ho Chong, a research scientist in the lab of Javier Luis Martinez, who led the collaboration. explains. “Also, these routes are clearly not sustainable,” he adds.
These challenges in butadiene production have sparked renewed interest in the Lebedev process, first developed in the 1930s to convert ethanol to butadiene in a single catalytic reactor. “Sustainable butadiene can be produced using bioethanol in the Lebedev process or using ethanol produced using the state-of-the-art he CO2-to-ethanol process,” he said. Chung says.
The Lebedev process is driven by a silica-magnesia catalyst manufactured by a special method called wet-kneading. The method includes mixing a solid catalyst precursor in water with continuous mixing. “Wet kneading is very uncommon in catalyst preparation, but it is often applied to the preparation of high-performance silica-magnesia catalysts for the Lebedev process,” he says Ruiz-Martinez.
However, improved wet-kneaded catalysts have been discovered primarily through trial and error. It is not fully understood why some catalysts are better than others, saying that “understanding how these materials are formed is the key to preparing better catalysts.” It’s the first step,” he says Ruiz-Martinez.
Colleagues in Chung, Ruiz-Martinez, and KAUST used solid-state nuclear magnetic resonance spectroscopy to study the formation of silica–magnesia catalysts under real wet-kneading conditions. “We found that two different catalyst particles were formed based on the cross-deposition of silicon species onto magnesia and of magnesium species onto silica,” he says.
Importantly, they showed that magnesium silicate on silica particles tends to produce ethylene as an undesirable by-product. and avoid ethylene-producing particles,” says Chung. The team also showed that the best catalysts have specific active sites in close proximity.
“This helped us work on next-generation catalysts for this process,” says Ruiz-Martinez. “We are well on our way and already have a more selective version that could be an important step in commercializing the process.”
Original: Renewable route to rubber material
Than: King Abdullah University of Science and Technology
